Aeration

ABSTRACT

SURFACE AERATION APPARATUS FOR TREATING EFFLUENT LIQUID IN WHICH BAFFLE PLATES ARE MOUNTED BELOW A ROTATABLE SURFACE AERATOR AND ARE ARRANGED TO OPPOSED ANY TENDENCY FOR THE EFFLUENT LIQUID TO BE ROTATED AS A BODY WITH THE AERATOR.

United States Patent O 3,606,983 CARBURETOR HAVING AN AUTOMATIC CHOKE Robert D. Mitchell, Madison Heights, Mich., assignor to Holley Carburetor Company, Warren, Mich. Filed Apr. 21, 1969, Ser. No. 817,636 Int. Cl. F02m 1/08 US. Cl. 261-39 12 Claims ABSTRACT OF THE DISCLOSURE A carburetor, having a choke valve with thermostatic means adapted to urge the choke valve in the closing direction when cold, is provided with pressure responsive means which communicates with a source of engine vacuum for moving the choke valve in a direction opposite to that of the thermostatic means upon engine starting; the degree of effective communication between the pressure responsive means and the source of engine vacuum is controlled in accordance With the position of the carburetor throttle valve in order that the pressure responsive means will be effective for moving the choke valve to a first partly opened position when the throttle valve is in its nominally closed position and to a variable second more fully opened position when the throttle valve is moved to a part throttle position.

BACKGROUND OF .THE INVENTION Heretofore, automatic choke mechanisms have employed either a diaphragm assembly or a pressure responsive piston in communication with a source of engine or intake manifold vacuum for moving the choke valve, against the resisting force of a thermostat tending to close the choke valve, to a partially open position, often referred to as the qualifying position, after a cold or relatively cold engine has been started. A stepped fast idle cam positioned by choke valve position then controlled idle throttle position.

It has also become accepted practice, in the prior art, to make such pressure responsive diaphragms or pistons of the stopped type; that is with either the stopped diaphragm or piston the initial qualifying position of the choke valve is determined by a positive mechanical stop which precludes any further movement of such diaphragm or piston in the choke opening direction.

However, one disadvantage of the prior art arrangements, including the stopped type of diaphragm or piston employed by the prior art, is that there is no control or modulation of the choke position when the engine operating conditions are changed from cold fast idle to cold engine drive-away. Another disadvantage is that prior art choke systems result in a single fixed qualifying choke valve position for the higher air flow steps on the fast idle cam.

That is, it is generally well known that a cold engine requires a combustible mixture which is of a richer fuelair ratio during cold idle engine operation in order to sustain engine operation and the initial choke opening is selected in order to achieve such a richer mixture. However, upon undergoing cold drive-away conditions, at which higher engine speeds are also experienced, that initial opening of the choke valve usually results in an overly rich fuel-air ratio. This in turn results in the emission of unburned hydrocarbons, a reduction in overall fuel economy and often rough or sporadic engine operation.

The invention as herein disclosed and described is directly concerned with the solution of the above as well as other problems.

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SUMMARY OF THE INVENTION According to the invention, a carburetor for an inter- .nal combustion engine comprises a choke valve, a throtpressure responsive means being effective to move said choke valve to a first partly open position when said engine starts and the throttle valve is in its cold or fast idle (closed) position, said pressure responsive means also being effective to move said choke valve to a variable second partly open position more nearly fully open'ed than said first partly open position when said throttle valve is moved from its above-defined idle or closed position toward a part-throttle position.

Accordingly, a general object of the invention is to provide in a carburetor having a choke valve, means for positioning the choke valve in a first partly opened position when the throttle valve is closed and for also positioning the choke valve in a variable second partly opened position more fully opened than said first partly opened position when the throttle valve is moved away from its said closed position to any higher air flow position.

Other more specific objects and advantages of the invention will become apparent when reference is made to the following detailed description and accompanying drawings.

DESCRIPTION OF THE DRAWINGS In the drawings, wherein certain details may be omitted from one or more views for purposes of clarity:

BIG. 1 is a side elevational view of a carburetor, with portions thereof broken away and in cross-section, constructed in accordance with the teachings of the invention.

FIG. 2 is an enlarged fragmentary view of a portion of the carburetor of FIG. 1 sectioned axially through a cooperating pressure responsive choke actuating means constructed in accordance with the teachings of the invention;

FIG. 3 is a fragmentary cross-sectional view, similar to FIG. 2, but of a second embodiment of the invention; and

FIG. 4 is an enlarged fragmentary portion of FIG. 1 illustrating in greater detail certain of the elements shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now in greater detail to the drawings, FIG. 1 illustrates a carburetor 10, constructed in accordance with the invention, as comprising a carburetor body 12 formed to provide an induction passage 14 having the usual venturi restriction 16 and a throttle valve 18, Within the induction passage downstream of the venturi 16, pivotally mounted on manually positionable throttle shaft 20. The entire carburetor assembly is suitably secured atop an engine intake manifold 22.

The throttle valve is opened, against the force of a spring 24 urging it closed, in the usual manner as by means of suitable linkage 26 connected between the throttle lever 28 and the operators foot pedal (not shown). As is customary, closure of the throttle 18 may be limited by an adjustable stop screw 30 adapted to be ro tated with the throttle valve and engageable with one of a plurality of cam-like steps (not shown) formed on a fast idle cam (fragmentarily illustrated at 32) which is positioned generally by the choke mechanism 34 as through a lost motion linkage member 36.

9P 21, 1 w. S.ROBERTSON 3,606,984

AERATION Filed May 9, 1968 3 Sheets-Sheet 5 FIG.3

3,606,984 AERATION William Swan Robertson, Manchester, England, assignor to Simon-Carves Limited, Cheadle Heath, Stockport, England Filed May 9, 1968, Ser. No. 727,802 Claims priority, application Great Britain, May 17, 1967, 22,936/ 67 Int. Cl. C02c 1/10 U.S. Cl. 261-91 11 Claims ABSTRACT OF THE DISCLOSURE Surface aeration apparatus for treating efiluent liquid in which bafile plates are mounted below a rotatable surface aerator and are arranged to oppose any tendency for the efiiuent liquid to be rotated as a body with the aerator.

This invention is concerned with improvements in or relating to surface aeration.

In the surface aeration of, for example effiuent liquids, e.g. industrial eflluents and municipal sewage, using rotatable surface aerator members, at times when the liquid being aerated is shallow in depth, liquid tends to rotate as a body with the aerator member and this leads to inefficient aeration characteristics. This is a particular problem with large aeration lagoons where side walls of the lagoon are so far away from the aerator member as not substantially to affect the hydrodynamic conditions around the aerator member, and with circular aeration tanks.

It is an object of the invention to provide an improved surface aeration apparatus.

It is another object of the invention to provide an improved eflluent liquid treatment plant comprising such an apparatus.

According to the present invention, there is provided a surface aeration apparatus comprising a rotatable surface aerator member and a plurality of radially disposed baffle plates provided around the axis of rotation of the aerator member and below the aerator member so as to control rotation of liquid being aerated as a body with the aerator member during operation of the apparatus, the distance between the inner end of each baffie plate and the axis of rotation of the aerator member is between 0.2 and 0.5 of the diameter of the aerator member.

The apparatus is particularly useful where the depth of the liquid being aerated is not more than 1.7 times the diameter of the aerator member, when the aerator member is circular in plan view.

According to another aspect of the present invention there is provided effiuent liquid treatment plant including surface aeration apparatus as defined above.

The aerator member is used, for example, in a large aeration lagoon where side walls of the lagoon are so far away from the aerator member as not substantially to affect the hydrodynamic conditions around the aerator member, or in an aeration tank which is circular in plan view.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a sectional side view of surface aeration apparatus of an effiuent liquid treatment plant;

FIG. 2 is a plan view of parts of the apparatus of FIG. 1, and

FIG. 3 is an over-all plan view of the apparatus of FIG. 1.

Referring to the drawings, the plant includes surface aeration apparatus comprising a large aeration lagoon 12 United States Patent 3,606,984 Patented Sept. 21, 1971 with side walls 13 provided in the ground and containing an eflluent liquid which comprises, for example, an industrial efiluent or municipal sewage. The lagoon 12 also contains activated sludge adapted to treat the liquid for disposal. A rotatable surface aerator member 18 is mounted in the lagoon 12 and is rotated in the operation of the apparatus to aerate the liquid. Due to the size of the lagoon 12 side walls 13 of the lagoon 12 are so far away from the aerator member 18 as not substantially to affect the hydrodynamic conditions around the aerator member 18. The lagoon 12 is provided with an inlet pipe 16 and an adjustable outlet weir 14 and, in the operation of the apparatus, liquid flows continuously through the lagoon 12 entering by the pipe 16 and leaving by the weir 14.

The apparatus also comprises baffle means mounted in the lagoon 12 below the aerator member 1 8 and arranged to oppose in the operation of the apparatus, any tendency of the liquid to be rotated as a body with the aerator member 18. The bafile means comprises four vertical substantially planar baflles 44 each of which extends upwardly for a short distance from the bottom of the lagoon 12. The baflles 44 are symmetrically disposed around the axis of rotation of the aerator member 18 radially to said axis, a central space 45 being left between the baffles 44 (see particularly FIG. 2).

The aerator member 18 corresponds generally in construction and arrangement with the aerator member de scribed in our UK. patent specification No. 919,467 to which reference may be made. The aerator member 18 is mounted for rotation on a vertical shaft 20 and comprises an inverted frusto-conical shell 32 which is symmetrical about the shaft 20, a circular cylindrical boss 31 of small diameter secured to, and extending downwardly from, the shell 32 coaxially therewith the shaft 20 being secured in the boss 31, and a plurality of arms 33 each of which lies in a vertical plane and is secured to the boss 31, extending tangentially to the boss 31 along the lower surface of the shell 32; each arm 33 has an end portion 35 extending outwardly from the outer periphery of the shell 32; each end portion 35 has a horizontal upper edge coplanar with the outer periphery of the shell 32, and has a horizontal plate 36 which extends circumferentially from the said edge on the side of the arm 33 remote from the boss 31, and outwardly from the outer periphery of the shell 32,. In the operation of the apparatus the aerator member 18 is rotated in the sense in which the plates 3-6 extend circumferentially from the arms '33.

The aerator member 18 is supported for rotation by a structure on which is supported a motor 62 and a gear-box 64 arranged to rotate the shaft 20; the structure 60 is itself supported on the bottom of the lagoon 12. The motor 62 and the gear-box 64 are mounted on a platform 63 which is secured to the structure 60 by jacking screws 65; the level of the aerator member 18 is adjustable by adjustment of the jacketing screws 65.

Each bafile 44 extends upwardly from a fiat elongated member 70. Outer end portions of the members are secured to the structure 60 and inner end portions thereof are secured to a horizontal plate 67 which is provided to prevent scouring of the bottom of the lagoon 12.

The baffies 44 are particularly useful when the depth D of the liquid is not more than 1.7 times the diameter d of the aerator member 18 measured across the shell 32. The distance between the inner end of each bafiie 44 and the axis of rotation of the aerator member 18 is between 02d and 05d, preferably about 0250!. Four bafiles being used, the height h of each baflle 44 is not less than 0.25D and its length L not less than 0-.75d, the product Lh being not less than 0.25D; preferable bafflle dimensions are either L d, h=0.25D or alternatively L=0.75a', h=0.4-D'.

What is claimed is:

1. Surface aeration apparatus for the treatment of effluent 'liquor comprising a rotatable surface aerator member and a plurality of radially disposed bafile plates provided around the axis of rotation of the aerator mem her and below the aerator member so as to control rotation of liquor being aerated as a body with the aerator member during operation of the apparatus, the distance between the inner end of each baffle plate and the axis of rotation of the aerator member is between 0.2 and 0.5 of the diameter of the aerator member.

2. Apparatus as claimed in claim 1, wherein the aerator is circular in plan view and the arrangement is such that, during operation of the apparatus, the depth of the liquid is not more than 1.7 times the diameter of the aerator member.

3. Apparatus as claimed in claim 1, wherein the distance between the inner end of each bafile plate and the axis of rotation of the aerator member is about 0.25 of the diameter of the aerator member.

4. Apparatus as claimed in claim 1, wherein the bafiles are adapted to be located on the bottom of a tank in which the apparatus is used.

5. Apparatus as claimed in claim 1, wherein the baffie means is connected with a support carrying the aerator 8. Apparatus as claimed in claim 1, wherein four equally spaced bafile plates are provided.

9. Apparatus as claimed in claim 4, wherein the height of each baffle plate is not less than 0.25 of the depth of the liquid, the length of each baffle plate is not less than 0.75 of the diameter of the aerator member and the product of the said length and the said height is not less than 0.25 of the product of the diameter of the aerator member and the depth of the liquid.

10. Apparatus as claimed in claim 9, wherein the length of each bafile plate is equal to the diameter of the aerator member and the height of each baffle plate is 0.25 of the depth of the liquid.

11. Apparatus as claimed in claim 9, wherein the length of each baffle plate is 0.75 of the diameter of the aerator member and the height of each bafile plate is 0.4- of the depth of the liquid.

References Cited UNITED STATES PATENTS 983,037 1/1911 Feld 261 91 2,527,015 10/ 1950 Lhota 26 1-91 2,744,737 5/1956 Vliet 26191 3,182,972 5/1965 Alsop et al. 2l02l9X FOREIGN PATENTS 244,444 10/1962 Australia 26191 25,218 11/1912 Great Britain 26191 TIM R. MILES, Primary Examiner U.S. Cl. X.R. 2l0219 

